Pokemon R/B/Y - Possible stat modifier AI oversight
44The Pokemon Red/Blue/Yellow second AI layer encourages the use of stat up and down moves such as Growl and Swords Dance during the opponent's second turn, despite it'd make the most sense to encourage them in the first turn instead in order to maximize their potential. This is achieved by incrementing a certain address (ccd5) and encouraging stat modifying moves only during the turn that address contains exactly 1. ccd5 is cleared whenever an opponent's Pokemon faints, meaning it applies to every Pokemon's second turn.
Note that while there is another AI layer (layer 3), that discourages not very effective or ineffective moves, it only weighs them against other damaging moves, meaning that if there is no neutral or super-effective move to use, ineffective moves won't be discouraged. That's why the Cubone in the video kept using Bone Club.
Note that the AI layers 2 and 3 are not shared by every trainer class. Only the layer 1 is, with the exception of Youngster and Cue Ball (AI layer 1 discourages status moves when the player is already statused).